1. Field of the Invention
The present invention relates to a method of producing a sintered body of yttrium-aluminum garnet, a sintering aid therefor, and a sintered body produced by the method.
2. Related Art Statement
Yttrium-aluminum garnet (Y3Al5O12: YAG) ceramics has an excellent transmittance over a wide range of wavelengths from visible to infrared lights. Applications of the ceramics such as a substitute material for a sapphire window, a material for a vessel for a discharge lamp and a corrosion resistant member have been studied.
Yttrium-aluminum garnet, however, has a melting point of about 1950° C. and thus requires a high sintering temperature so that the reduction of the production cost is rather difficult. For example, according to a Japanese Patent publication 5-286, 761A, alumina powder and yttria powder are mixed with a sintering aid added, shaped and sintered at 1600 to 1860° C. The sintering aid includes lithium oxide, sodium oxide, magnesium oxide, calcium oxide and silicon oxide.